Spherical metal powder is used as raw material and electron beam is used as energy source. At the beginning of the process, powder is evenly spread on a specific metal base plate, and the powder is slightly sintered by powder bed preheating. The 2D data is melted over a selection of the powder bed to form a cross section of the part. Then the bottom plate is lowered by one layer, and the above process is repeated, and the design part is finally formed. The entire molding process is kept in a high vacuum environment (10-3Pa) to prevent oxidation or nitridation of metal parts and powders
